Camp Century, which was shut down in 1967, was buried deep underneath the surface ice on the remote Danish territory of Greenland during the height of the Cold War.

Military chiefs had intended to use the secretive base in order to prepare for possible war with the Soviet Union, giving the US the option to launch strikes from just hundreds of miles away from the enemy.

The jaw-dropping underground community, known as “The City Underneath The Ice”, played host to more than 200 soldiers among its three-kilometre network of tunnels.

Soldiers had their own living quarters, a shop, a hospital, a chapel and even a cinema.

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MYSTERIOUS: Camp Century in Greenland is slowly being uncovered by melting ice

But in 1967, Camp Century was abandoned amid fears that the ice was too unstable to support the top secret activities happening beneath.

Engineers conceded that a collapse was a likely possibility and soldiers were forced to withdraw from the location.

Vital equipment was removed from the site but parts of the camp’s infrastructure remained – including all biological, chemical and radioactive waste.

It had been hoped that the camp would lie buried in the snow forever, along with its toxic contents – but global warming looks certain to ensure the base will be uncovered in a matter of years.

Greenland experienced one of its hottest years on record last summer, touching 24 degrees celsius in the capital, Nuuk, in June.

“Every year, another layer of ice will be removed,” William Colgan, a climate and glacier scientist from the Lassonde school of engineering at Toronto’s York University, told The Guardian.

When it was built in 1959, the base was only 8m below the surface ice level.

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DANGER: The melt could release harmful pollutants into the atmosphere

Almost 50 years later, persistent snow and icefall have seen the base sink to 35m deep.

But the inevitable melt caused by global warming has the potential to expose an estimate of around 200,000 litres of diesel fuel, similar quantities of wastewater, unknown amounts of radioactive coolant and toxic organic pollutants into the atmosphere.

“Our estimate is that by 2090, the exposure [of the base] will be irreversible,” Colgan added.

“It could happen sooner if the magnitude of climate change accelerates.”